1. Field of the Invention
The invention disclosed and taught herein relates generally to valves; and more specifically relates to indicating the position of linear- and rotary-motion control valves.
2. Description of the Related Art
Various types of linear- and rotary-motion type valves are known in the art. There is often a need to know or monitor one or more statuses of a valve during use, such as whether or to what extent the valve is open or closed. The indicator devices presently available typically provide one of two forms of indication of the position of a control valve: electrical or visual mechanical. The visual mechanical indicators include various forms of mechanically driven indicating devices that can translate mechanical motion of the shaft of the control valve, whether it is linear or rotary, to a change in color to indicate whether the control valve is in the open or closed position. In conjunction with this mechanical visual indication can be an electrical means that provides a corresponding electrical signal for the open and closed positions of the control valve. The indicators of the present state of the art can be bulky or costly to produce. Examples of present indicators include U.S. Pat. No. 6,242,909 to Dorsey et al., and No. 6,742,541 to Pimouguet, each of which is assigned to the assignee of the present invention and incorporated herein by reference for all purposes. Other examples include U.S. patent application Pub. No. 2008/0078462 to Minervini et al., which is incorporated herein by reference for all purposes.
The examples mentioned above share common design traits in that they include electrical enclosures that house the switching means and are coupled to a mechanical visual indicator. The construction of devices such as these can become cumbersome and expensive based on a number of factors or operating conditions, such as temperature, humidity, water ingress protection or restrictions based on hazardous conditions or locations. Large aluminum or stainless steel die castings, precision machining of surfaces and extensive gasketing of the valve indicator enclosures may often be required to meet the demands of a particular application, which may nonetheless include undesired spaces within the enclosures into which water, air, or other unwanted substances may enter. While each of the mentioned examples may have certain limited applications, there is a need to improve the construction of valve indicators.
The invention disclosed and taught herein is directed to an improved system for valve status indicating and to methods of making and using the same.